1. Field of the Invention
Embodiments of the present invention relate to a wireless LAN (local area network) communication system, and in particular to a method for analyzing data transmission throughput in a European Telecommunication Standards Institute (ETSI) wireless LAN communication system.
2. Background of Related Art
In a wireless LAN (local area network) communication system, there are systems based on the IEEE (Institute of Electrical and Electronics Engineers) of U.S. and systems based on the ETSI (European Telecommunication Standards Institute) of Europe. In particular, an IEEE 802.11a system is representative of the IEEE, and ETSI BRAN HIPERLAN/2 (hereinafter referred to as H/2) system is representative of the ETSI.
FIG. 1 is a view illustrating a wireless LAN communication system according to an example arrangement. Other arrangements are also possible. The wireless LAN communication system may include plural Mobile Terminals MTs 10, 15 that include PCs (personal computers), processing/storing/outputting received data and transmitting/receiving data wirelessly with the other parties through a path set while moving within a certain area. The wireless LAN system may further include an AP (access point) 20 wirelessly connected with the plural terminals 10, 15 in order to set a request path and transmit/receive pertinent data wirelessly as well as a public communication network 30 for connecting the terminals 10, 15 to another network through the AP 20.
The terminal may include a movable (or mobile) PC, etc., that performs numerous functions including inputs/processes/outputs data for itself, transmits/receives pertinent data to/from another terminal 15 wirelessly connected through the AP 20, simultaneously contacts to a MT (terminal) of another network through the public communication network 30 and transmits/receives pertinent data.
The plural terminals 10, 15 contact to the AP 20 from a LAN (local area network). The LAN is a wireless LAN because data is transmitted by wireless contact.
In the wireless LAN, a contact method may be provided in which the AP 20 contacts the other party. An ad-hoc method may also be provided in which each terminal 10, 15 directly contacts the other terminals 10, 15 without the AP 20.
FIG. 2 shows a MAC frame of an ETSI wireless LAN. In the ETSI wireless LAN, data is transmitted/received by MAC frame units. Each terminal 10, 15 may classify wirelessly transmitted/received data by the MAC frame units having a certain size. In the ETSI BRAN HIPERLAN/2, one MAC frame is 2 ms and consists of 500 OFDM symbols. The one MAC frame may include a signaling Protocol Data Unit (PDU) and a data PDU.
The signaling PDU may include a Broadcasting Channel (BCH) for transmitting a notification to all the terminals 10, 15 in a service area; a Frame Channel (FCH) for describing a structure of the MAC frame; an Access Feedback Channel (ACH) for reporting a result about a channel allocation request; and a Random Access Channel (RCH) for requesting allocation of a channel as a data send/receive path. The BCH, FCH and ACH are provided ahead of the data PDU, and the RCH is provided behind the data PDU.
The data PDU may include a UL (UP-LINK) PDU for upward transmission data; a DiL (direct link) PDU used in the ad-hoc method in which the plural terminals 10, 15 directly contact each other without the AP 20; and a DL (DOWN LINK) PDU for downward transmission data. The DiL PDU may be optional.
In the wireless LAN using the MAC frame, a PDU for transmitting user data is a data PDU, and throughput of the wireless LAN may be determined by a size of transmitted user data and/or the number of symbols.
FIG. 3 is a flow chart illustrating a general method for analyzing data transmission throughput in a wireless LAN according to an example arrangement. Other arrangements are also possible. A data transmission throughput analyzing method may include calculating a number of OFDM symbols transmitted through a Long Transmit Channel (LCH) in the wireless LAN using a single sector as shown at steps S10 and S20. The method may also include analyzing data transmission throughput using the calculated number of symbols.
More specifically, in the throughput analyzing method, a number of symbols of the signaling PDU of the MAC frame used in the wireless LAN constructing the single sector is calculated. The number of symbols of the data PDU (except the LCH) is calculated, and the calculated number of symbols of the signaling PDU and the number of symbols of the data PDU (except the LCH) are subtracted from the number of OFDM symbols set in the one MAC frame, as shown at steps S10 and S20. The result of the subtraction is the number of OFDM symbols transmitted through the LCH. The data transmission throughput may be determined by the subtraction result value as shown at step S30.
As described above, the data transmission throughput analyzing method may analyze data transmission throughput of the MAC frame used in the omni type wireless LAN not having directiveness (i.e., in the wireless LAN constructed as the single sector).
However, in a wireless LAN constructed of multi sectors, classifying service areas into certain regions when data transmission throughput is analyzed, in case of using the data transmission throughput analyzing method described above, data transmission throughput cannot be accurately analyzed because data transmission throughput is analyzed without reflecting a section switch guard time for classifying each sector.
In the data transmission throughput analyzing method, data transmission throughput cannot be accurately analyzed because the number of OFDM symbols occupied by a propagation delay guard time for classifying transmission data by terminals is not reflected.
In addition, in the data transmission throughput analyzing method described above, because data transmission throughput using the ad-hoc method is not analyzed, OFDM symbols occupied by the DiL PDU cannot be reflected, and the data transmission throughput cannot be accurately analyzed.